Latency In vitro of varicella-zoster virus in cells derived from human fetal dorsal root ganglia

A potential in vitro model of varicella-zoster virus (VZV) latency was developed. Dissociated human dorsal root ganglion cultures were infected with VZV and maintained for 1 wk in the presence of bromovinyl arabi-nosyl uracil, a potent inhibitor of VZV. Seven to 21 d after removing the inhibitor (>14 d after infection), the cells were trypsinized, passed to monolayers of human embry­onic lung fibroblasts, and observed for VZV reactivation as indicated by typical cytopathic effects and the appear­ance of VZV antigens. VZV reactivated from 56% of the cultures containing both neurons and satellite cells but not from cultures specifically enriched for either neurons, sat­ellite cells, or ganglion-derived fibroblasts. The failure to isolate VZV from cell suspensions that were sonicated before cocultivation with fibroblasts indicated that infec­tious VZV was not present before reactivation. Moreover, immunohistochemical and immunoprecipitation studies re­vealed no VZV-specific antigens in any cultures before the reactivation stimulus. VZV antigens were detected after trypsinization and cocultivation. These findings suggest that cultures containing both neurons and satellite cells provide a model system for VZV persistence that possesses many properties of a latent infection.